This contract is divided into two different tasks. The primary goal of these studies is to develop a safety and toxicity profile on Oltipraz so that an appropriate and safe dose for a subsequent risk reduction trial can be established. It is also necessary to obtain required information so that an application for a Phase II IND can be submitted to the FDA prior to a cancer risk reduction trial. A secondary objective is to obtain pharmacokinetic data on Oltipraz, and on its metabolites if possible, so that a maximum body of knowledge concerning the distribution, metabolism, excretion, and toxicity of the compound will be available. Such data may enhance the efficacy and safety of that compound in the prevention trials(s) to be developed subsequently.